/**
 * #      183
 * 名称   从不订购的客户
 * 链接   https://leetcode-cn.com/problems/customers-who-never-order
 * 题解   [417](https://leetcode-cn.com/problems/customers-who-never-order/solution)
 * 通过率 67.7%
 * 难道   简单
 */

